Background/Purpose Autoimmune bullous diseases (AIBDs) are rare conditions that can affect daily life and be life-threatening. However, there is scant research on Thai patients with oral AIBDs.Materials and methodsRetrospective analysis of the characteristics, distribution, and treatment outcomes of oral AIBDs in Thai patients (20-year period).ResultsEighty-two oral AIBDs patients were diagnosed, mostly female ages ranging from middle-aged to elderly. The most common subtype was pemphigus vulgaris (PV) (59.8 %), followed by mucous membrane pemphigoid (MMP) (26.8 %), bullous pemphigoid (BP) (8.5 %), and linear IgA bullous dermatosis (LABD) (4.9 %). The gingiva was the most affected site. Notably, 81.8 % of MMP patients had only oral lesions (mostly gingiva), while most PV patients had multiple lesions, with oral lesions often appearing first. Corticosteroids (CS) (topical and/or systemic) were the primary treatment. The overall response rate for control of disease activity (CDA) was 73.9 %, with complete remission (CR) in 17.4 %. Patients receiving only topical CS had fewer side effects (66.7 % reported none, others mild) compared with combined therapy (48.6 % reported side effects).ConclusionPV was the most prevalent subtype, often presenting with oral and skin lesions, with oral lesions appearing first. Conversely, MMP primarily manifested as isolated oral lesions, often with desquamative gingivitis. Combination therapy with topical and systemic CS was the most common treatment for oral AIBDs. Notably, patients treated with topical CS only experienced significantly fewer and milder side effects compared with those receiving other treatments.